Superconducting cable

The cables house 36 strands of superconducting wire, each strand being
exactly 0.825 mm in diameter. Each strand houses 6300 superconducting
filaments of Niobium-titanium (NbTi). Each filament is about 0.006 mm
thick, i.e.
10 times thinner than a normal human hair.

Cable

Strand

Filaments

Around each filament there
is a 0.0005 mm layer of high-purity copper. Based on physical measurements
it is a Rutherford cable, 1.510 cm broad, the mid-thickness being 1.480
mm, tolerances are only a few micrometers. Copper is an insulation
material between the filaments in the superconductive state, when the
temperature is below -263C. When leaving the superconductive state, copper
acts as a conductor transferring the electric current and the heat. Niobium-titanium
is an superconducting alloy. (c/o http://www.cus.cam.ac.uk/~bag10/LHC.html)

Or according to Furukawa Electric (we have two main suppliers of superconducting
cable): This niobium-titanium superconducting cable is thirty six stranded
and
roll
formed by special
equipment and
technology in a cuneal cross section with a width of 15.1 millimeters
and an average thickness of 1.48 millimeter strands. Each strand contains
6,426 twisted niobium-titanium filaments with a diameter of 6-micrometers
embedded in an oxygen free copper matrix.

Total superconducting cable required 1200 tonnes which translates to
around 7600 km of cable (the cable is made up of strands which is made
of filaments, total length of filaments is astronomical - 5 times to
the sun and back with enough left over for a few trips to the moon).